W. £2 Hidden—Mazapu Meteoric-iron. 221 
of uplifts, each separated from the others by a period in 
which the land remained in the same relative position to the 
sea for a period of time sufficiently long to permit the waves to 
excavate a strongly marked bench while in the intermediate 
sections the elevation took place so rapidly that the drift coat- 
ing was not swept away from the rocks. It seems at present 
likely that these benches on Mt. Desert do not correspond with 
any similar coast lines in the southern part of New England. If 
this is proved to be the case then we have evidence that the 
rate and manner of upward movement were very diverse in 
regions which are close together. 
Although in this paper I propose to limit the matter of in- 
quiry in the main to the post-glacial changes which have come 
upon the valleys of the northward-flowing streams it may be 
noticed that the facts above referred to throw much light upon 
the preglacial attitude of the continent. These river-valleys 
retain the general form which they had before the last glacial ice 
began to act upon them, they pursue their present courses be- 
cause their flow is mainly determined by the existence of the 
pre-glacial river valleys in which they le. It is clear that these 
valleys could not have been excavated by streams of their pres- 
ent slope, it seems, therefore, necessary to assume that the 
descent of the northward flowing rivers must have been more 
rapid in the pre-glacial times than it is at present, or, in other 
words, this part of the continent was at that time relatively less 
elevated in its northern parts than it is at present. 
ArT. XXV.—On the Mazapil Meteoric-iron, which fell November 
27th, 1885;* by WiLL1AM Hart HIDDEN. 
AMoNG the large number of meteoric irons which have been 
described, only eight+ are recorded as having been seen to 
fall. It is my privilege to be able to add a ninth fall to this 
short list, and one which may prove to be of exceptional scien- 
tific importance. This mass of meteoric iron I received in 
August last as a gift from my friend, Professor José A.. y 
Bonilla, Director of the Astronomical Observatory at Zacatecas, 
Mexico. He stated that it was seen to fall at about 9 P. M. on 
the 27th of November, 1885, during the periodical star-shower 
of the “ Bielids.” Such is the great interest of this meteorite, 
* This meteorite was first announced on Jan. 17, 1887, before the New York 
Academy of Sciences, at a regular meeting. 
+ Agram, Croatia, May 26, 1751: Charlotte, Dickson Co., Tenn., Aug. 1, 1835; 
Braunau, Bohemia, July 14, 1847; Tabarz, Saxony, Oct. 18, 1854; Victoria-West, 
Africa, in 1862; Nejed, Arabia, spring of 1865; Nedagolla, India, Jan. 23, 1870; 
Rowton, Shropshire, England, April 20, 1876. See the catalogue of the meteor- 
ites in the Mineral Department of the British Museum, by L. Fletcher, p. 42. 
